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Arxiv: Tip of the Red Giant Branch Distances with JWST: An Absolute Calibration in NGC 4258 and First Applications to Type Ia Supernova Hosts Published: 1/9/2024 9:05:00 PM Updated: 4/26/2024 5:38:27 PM

Paper abstract: The tip of the red giant branch (TRGB) allows for the measurement of preciseand accurate distances to nearby galaxies, based on the brightest ascent oflow-mass red giant branch stars before they undergo the helium flash. With theadvent of JWST, there is great promise to utilize the technique to measuregalaxy distances out to at least 50 Mpc, significantly further than HST's reachof 20 Mpc. However, with any standard candle, it is first necessary to providean absolute reference. Here we use Cycle 1 data to provide an absolutecalibration in the F090W filter. F090W is most similar to the F814W filtercommonly used for TRGB measurements with HST, which had been adopted by thecommunity due to minimal dependence from the underlying metallicities and agesof stars. The imaging we use was taken in the outskirts of NGC 4258, which hasa direct geometrical distance measurement from the Keplerian motion of itswater megamaser. Utilizing several measurement techniques, we findM_{TRGB}^{F090W} = -4.362 \pm 0.033 (stat) \pm 0.045 (sys) mag (Vega) forthe metal-poor TRGB. We also perform measurements of the TRGB in two Type Iasupernova hosts, NGC 1559, and NGC 5584. We find good agreement between ourTRGB distances and previous distance determinations to these galaxies fromCepheids (\Delta = 0.01 \pm 0.06 mag), with these differences being toosmall to explain the Hubble tension (~0.17 mag). As a final bonus, weshowcase the serendipitous discovery of a faint dwarf galaxy near NGC 5584.